Grinding device



IETATSU OHNO GRINDING DEVICE Oct. 28, 1969 2 Sheets-Sheet 1 Filed Dec. 12, 1966 INVENTOR HTA TSU OHNO Oct. 28', 1969 I f ETATSU QHNO v 3,474,574

GRINDING DEVICE v Filed Dec'. 12, 1966 Y 2 Sheets-Sheet 2 INVENTOR mTATsU -oHNo BYl dfgg? United States Patent O 3,474,574 GRINDING DEVICE Ietatsu Olmo, Building 2-406, 1667 Mure, Mitaka, Tokyo, Japan Filed Dec. 12, 1966, Ser. No. 600,892 Claims priority, applicat7it6m 1Jlpan, Dec. 13, 1965,

3 5 Int. Cl. B24b 31/02 ABSTRACT F THE DISCLOSURE A grinding device for tumbling workpieces including a plurality of containers symmetrically mounted in a carrier. A plurality of carriers is mounted on the 'periphery of a drum for planetary movement. The workpieces and abrasive are carried in the containers.

This invention relates to a grinding device.

In the case where watch parts, knitting needles and injection syringes, for instance, are to be ground, if these and some suitable abrasives are put into closed containers attached around a rotary drum and the drum is rotated at high speed, a grinding action is carried on by the slight vibration which takes place while both the abrasives and the objects to be ground are kept in strong pressure contact by centrifugal force. Furthermore, with such a device, if said containers are given rotations themselves, they rotate and change their relative positions to said abrasives and objects to be ground, since said abrasives and objects to be ground always take their positions in the outer peripherie direction of said drum due to the centrifugal force. Consequently, that said abrasives and objects to be ground execute a flowing motion and the grinding eiciency is remarkably improved. In this case, however, a large pressure arises on the walls of said containers at the outer periphery of said drum because of the centrifugal force of said abrasives and objects to the ground. Because of this large frictional force at the farthest positions from the shafts of Said containers, a large driving force is required for the rotation of said containers and the vibrating noises of the device increase. The present invention provides a device which has no such defects and yet has very high grinding eciency. This is achieved by giving a plurality of such containers a self-rotation motion in an integrate manner.

In the accompanying drawings:

FIGURE 1 is the A-A section of FIGURE 2,

FIGURE 2, the B-B section of FIGURE l,

FIGURE 3, the C-C section of FIGURE l,

FIGURE 4, a longitudinal section of the grinding device,

FIGURE 5, a side view of a part of the grinding device cut longitudinally,

FIGURE 6 a view of the entire drum on C-C, including FIGURE 3.

The shaft 2 of the rotary drum 1 is supported by the base 3. The shaft 2 may be either fixed to or rotatably inserted in the drum 1, but, in either case, is provided at a side of the drum 1 with the clutch wheel 4 and the gear made integrally and inserted rotatably in it. Also the drum 1 has on its side the pulley 6 which is connected to the motor 8 by means of the belt 7, and at the same time it has the four pinions 9 journalled in its side, said pinions being engaged with said gear 5. Furthermore, the drum 1 has on its periphery four cylindrical rotary frames 10 rotatably supported on trunnions 35 whose arcs run parallel to the shaft 2 and are spaced radially therefrom, and one of the trunnions 35 of each rotary frame is provided wtih a gear 11. The

rotary frames are distributed on the periphery symmetrically about the shaft 2. These gears 11 have the same diameter as that of said gear 5, said gears 11 are engaged with said pinions 9. As seen in FIGURE 2, the shaft 12 fixed on the -base 3 supports rotatably an end of the clutch lever 13, the semi-arc part of the lever 13 facing to said clutch wheel 4. Said clutch wheel 4 has around its periphery a plurality of holes 14 and said semiarc part of lever 13 has a projection 15 which is inserted into one of said holes 14. When the lever 13 is placed at the position indicated in FIGURE 2, therefore, the clutch wheel 4 and the gear 5 can freely rotate, but when it is turned upwards in the direction of arrow p, said projection 15 is inserted into one of the holes 14 to make both said wheel 4 and said gear gear 5 stationary.

In each rotary frame 10 there are arranged four cylindrical containers 17 in parallel with the axis of the trunnion 35 of said rotary frame 10 and nearly symmetrical to said trunnion axis. These containers are fastened with the screw 19 through the keep plate 18, but as said screw 19 is screwed into the locking rod 20 rernovably inserted into the holes at both ends of said rotary frame 10, said containers 17 can be freely removed by loosening said screw 19 and removing said locking rod 20 from said rotary frame 10. The containers 17, as shown for one in detail in FIGURE 4 and FIGURE 5, have a cylindrical body permanently closed at one end with a cover 21 inserted at the open end. The cover 21 is held in place with screw 22, and as said screw 22 is screwed into a locking rod 23 inserted removably into holes of the container wall, said cover 21 can be removed by grasping the handle 24 after loosening the screw 22 and removing the locking rod 23.

The container 17 and the cover 21 are lined on their inside with a layer of rubber or plastic 25 to protect the objects to be ground in the container against damage by their rubbing against the container wall, and are provided with ribs 26 to strengthen the agitation and ow of the abrasives and the objects to be ground. In containers 17 are put optionally any objects to be ground 27, suitable abrasives 28 and a suitable volume of water, and the containers are set in the rotary frame 10.

Since the wheel 4 and the gear 5 can freely rotate when the clutch lever 13 is placed at the position shown in FIGURE 2, it is possible to move any required rotary frame 10 to come in front of the operator by turning the drum 1 and to make the opening of said rotary frame 10 face to the other side by turning the rotary frame 10. In this state the containers 17 containing the objects to be ground and the abrasives are set in each rotary frame 10 as shown in FIGURE 3. Then the wheel 4 and the gear 5 are fixed by turning the clutch lever 13 in the direction shown by the arrow p. If in this state the motor 8 is started, the drum 1 rotates, for instance, in the direction shown by the arrow a in FIGURE 2. Consequently, the pinions 9 rotate in the direction of the arrow b and the gears 11 in the direction of the arrow c, respectively. Since the gear 5 and the gears 11 have the same diameter, when the drum 1 resolves once, the gears 11 and consequently the rotary frame 10 also rotate once on their axes, in the direction opposite to that of the drum.

When the drum 1 revolves in the direction of arrow a in FIGURE 3, at 200 revolutions per minute for instance, the abrasives 28 and the objects 27 in the containers 17 experience centrifugal force in the radial direction of said drum and are pressed to the parts of the container walls which are radially outermost. The situation in all four frames is shown in FIGURE 6. As a result, the abrasives and the objects to be ground come yinto pressure-contact with each other. At the same time, because the rotary frame 10 rotates in the direction of arrow c, the abrasives and the objects to be ground execute a flowing motion as shown by the arrow d within the containers 17, in order that they can be kept always at the outer side of the drurn. FIGURE 6 shows this situation, Where the abrasive 28 and objects 27 to be ground always maintain a maximum distance from the shaft 2 when the drum is rotating. Also, the ribs 26 provided on the insides of the containers 17 help this owing motion to agitate the abrasives and the objects for quicker grinding. In other words, the abrasives and the objects to be ground not only contact each other with large pressure but also the abrasives slide on the surfaces of the objects to be ground due to the owing motion and agitation and the large friction between them due to the large contact pressure greatly increases the grinding efciency.

In each rotary frame 10, the plurality of containers 17 are arranged nearly symmetrically about the axes of trunnions 35. Consequently, in FIGURE 3, for instance, the frictional force of the abrasives and the objects to be ground exerted on the container walls acts in the direction opposite to the rotational direction of the rotary frame 10 as shown by the arrow x in the case of the container 17 at the exterior of the drum and increases the driving rotational force of said rotary frame, but the frictional force of the abrasives and the objects to be ground acts in the rotational direction of the rotary frame 10 as shown by the arrow y in the case of the container at the interior of the drum and significantly reduces the increase of the abovementioned driving rotational force. In the case of the two central containers located between the inner and outer containers, this offsetting action takes place between the right half and the left half of the same container.

In contrast, if a single large container containing a volume of the abrasives and the objects to be ground is mounted to the rotary frame 10, all rictional forces due to the abrasive and objects act to increase the rotational driving force of the frame. By distributing the same volume of abrasive and objects to be ground into a plurality of containers arranged nearly symmetrically about the axes of trunnions 35, the individual components of friction force tend to cancel one another, as explained in the last paragraph.

It is easy to revolve only the drum 1 with the rotary frames 10 stopped. The driving force for revolving the drum 1 is mostly consumed by the rotation of the rotary frames 10, but in the present invention, due to the symmetrical distribution of pluralities of containers 17 in the frames 10, the energy consumed by the rotary frames 10 is very small and therefore the driving force required of the motor 8 for rotating the drum is remarkably reduced. In one application, the required driving force was reduced to one-fifth as compared with the case where the same volumes of the abrasives and the objects to be ground are put in a single container. Also, the grinding eliiciency was extremely high and good ground surfaces were obtained.

Since the required driving force is small, vibration and noise are remarkably reduced, and it is easy to produce a large device with this invention. Another advantage is that, because the diameter of each container 17 may be made small, thin and long objects such as needles can ow within abrasive while being kept parallel with the axis of the container. This prevents the damaging of such objects caused when they are allowed to cross each other and directly contact each other at the points of crossing, with the result that favorable grinding can be assured.

What is claimed is:

1. A grinding device, comprising a stationary base (3), a drum (l) mounted on the base and rotatable about an axis, a plurality of rotary frames (10) mounted on the periphery of the drum and rotatable about axes parallel to the rotation axis of the drum, the rotation axes of the frames spaced radially from the rotation axis of the drum, a plurality of containers (17) mounted tixedly in each rotary frame substantially symmetrically about the rotation axes of the rotary frames, abrasives (28) and objects (27) to be ground both situated in the containers, means to rotate the drum about its rotation axis, and means to rotate the rotary frames about their rotation axes.

2. A grinding device as claimed in claim 1, the means to rotate the drum and the means to rotate the rotary frames being matched such that, when the drum revolves once, the rotary frames also rotate once, in the direction opposite to that of the drum.

References Cited UNITED STATES PATENTS 125,360 4/1872 Weissenborn 51-164 X 947,855 2/ 1910 Sawyer 51-164 1,144,272 6/1915 West 5l-164 1,538,231 5/1925 Abbott 51-164 3,078,623 2/ 1963 Stanley 5 l-164 HAROLD D. WHITEHEAD, Primary Examiner 

